She has posted bail — but it’s still not Independence Day for the accused shake-down mistress of Yankee GM Brian Cashman.

Buxom blonde Louise Meanwell must stay on Rikers Island until at least tomorrow, when a Manhattan Supreme Court judge is scheduled to rule on whether to approve $300,000 in collateral being offered by her mom, banking executive Caroline Neathway.

Prosecutors are questioning the collateral, claiming they have secret evidence proving that Meanwell has repeatedly extorted and threatened her mother — and so may just be doing so again.

Meanwell is fighting a 52-count serial-stalking indictment accusing her of harassing Cashman.

“I would lay down my life for her,” Neathway, who works for Citibank, said after court yeterday.

“She is my child.”

Meanwell also denied the district attorney’s extortion claim.

“I am in no way extorting my mother — she wants her daughter out of these conditions,” she told The Post in a phone call from Rikers.